Three of the six people who died in a charter bus crash outside Little Rock, Ark. Friday were hurled from the bus, and one was partially ejected, state police said.

The bus careened off foggy I-40 near the U.S. Highway 167 interchange and collided with a part of the North Hills overpass, shearing the roof off the bus, police said. At least six people on the bus were hurt but have been treated and released from hospitals.

The driver was identified as 28-year-old Roberto Vasquez of Monroe, Michigan. Three employees of Vasquez Citrus and Hauling of Lake Placid, Florida, were transporting 19 workers from Monroe to Laredo, Texas.

Police did not discuss the nature of their work, but the company had advertised for seasonal farmworkers last spring on a Michigan jobs site, saying the work would end in November.

Officers were working with the Mexican consulate to notify the victims' families, said Col. Bill Bryant, the head of the Arkansas State Police.

Immigration and Customs Enforcement officers were called in, but only to help local authorities communicate with the Spanish-speaking survivors, according to ICE spokesman Bryan Cox. He said his agency was not pursuing any kind of criminal investigation of the people involved.

The driver was not hurt, according to police. They say the crash occurred on the westbound side of the interstate around 1 a.m. Friday.

A heavy storm had recently passed through the area and left light rain and fog in its wake, but it wasn't immediately known if weather played a role. Authorities say there's no indication that drugs or alcohol were involved in the crash.

National Transportation Safety Board spokesman Eric Weiss said the agency is conducting an investigation separate from the police investigation, and will look at safety issues related to the crash. He said investigators will focus on driver fatigue and how passengers were protected, but may look into other issues once they get on the scene.

Weiss didn't have a specific timeline for how long the investigation would take.

The owner of a Michigan company whose name is emblazoned on the bus said he'd just sold the vehicle. Jeff Lawson, who identified himself as the owner of Continental Charters in Detroit, told the Arkansas Democrat-Gazette newspaper that he sold the bus Saturday to a man who "said he needed a second bus to haul people from (Detroit) to Texas... and Florida."

The bus that crashed had "Continental" displayed on the side.

Lawson says that as part of the sale, he stipulated that the buyer remove the "Continental" lettering from the bus. He says Continental Charters did not have any scheduled routes in Arkansas on Thursday and does not regularly operate in the area.

Lawson says the bus he sold is a 1997 Van Hool that was most recently inspected by his company in February or March.

The interchange is a bit tricky, requiring drivers to change lanes if they want to follow the route numbers that brought them into the area. They have about a minute to chart a course and execute it.

Police diverted traffic through North Little Rock to the north interchange of Interstates 30 and 40, according to the Fox affiliate. Access to at least one westbound lane was re-opened at 3 a.m. Traffic was snarled for hours but all debris and the bus were towed away before daybreak.

The Associated Press contributed to this report.

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